Did I ruin my RO membranes?

[john henry]

I finished up my last boil of the season a few weeks ago. I did a 250 gallon rinse on my RO after the last run. I had planned to do a triple soap wash a good rinse and then store the membranes in preservative. HOWEVER... I waited several weeks to get my preservative so when I fired up the RO to do another rinse before the triple wash it smelled really bad. So I went ahead and did a short rinse - 3 soap washes taking the temp to @ 110* with a short rinse between each. Then rinsed with @ 150 gallon of permeate. After this the concentrate discharge still smelled a little like cabbage? and the permeate discharge had a little smell too... I have a homebuilt RO with 2 4x40 MES membranes. Are they ruined? Do you have any recommendations on where to go from here? Any help would be greatly appreciated.

[bill m]

did you change the prefilter?

[Bricklayer]

Do a soap wash. Bring to temperature. And let the soap sit in the RO for a couple days. Make sure you have your PH at the highest the Membrane can take. Use a new pre filter.
Letting it soak might help get it in deeper. Rinse and repeat. Acid wash might help but the soap will do the bulk of the cleaning

[john henry]

Thanks for the replies! Started with a new prefilter and changed it between each soap wash and again before the last rinse.

[bowhunter]

Be careful letting the membrane sit very long in a high pH wash. Most membrane manufacturers would recommend against it... one or two hours maximum. High pH will eventually destroy the membrane. The membrane is probably fine. Bacterial growth is making it stink. Once you've removed as much of the odor as you can doing soap washes. You probably can just store it in the sodium bisulfite solution over the summer and it will be fine. This is a antibacterial material used for sanitizing wine making equipment and it should kill any remaining bacteria in the membrane. Make sure you soap wash it a couple of times before you use it next season.

[wiam]

I asked mes about membranes sitting in wash solution overnight many years ago. This is the reply I got.



A pH of 10.5 or less no issue. pH above that yes. That being said it probably wouldnt show issues first few times.

It will loosen up membrane if over and could start passing. Just look at permeate for sugar.

Clayton

Maple Expert Solutions, Inc
clayton@mapleexperts.com
603.359.8963

[john henry]

There is a lot of good advice here thanks to each one!